Best Coding Practices With Example

1. Follow a Consistent Coding Style

• Use a consistent indentation, naming conventions, and file organization.

• Python: use PEP8 style.

• JavaScript: use camelCase for variables/functions, PascalCase for classes.

Example (Python):

# Bad
def sum(a,b):return a+b

# Good
def sum_two_numbers(a, b):
    return a + b

Example (JavaScript):

// Bad
function sum(a,b){return a+b}

// Good
function sumTwoNumbers(a, b) {
    return a + b;
}

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2. Write Meaningful Names

• Variables, functions, and classes should clearly describe their purpose.

# Bad
x = 10
y = 20
z = x + y

# Good
num_apples = 10
num_oranges = 20
total_fruits = num_apples + num_oranges

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3. Keep Functions/Methods Small

• Each function should do one thing only.

• Easier to test and maintain.

# Bad
def process_order(order):
    # validate
    # calculate total
    # update inventory
    # send email
    pass

# Good
def validate_order(order):
    pass

def calculate_total(order):
    pass

def update_inventory(order):
    pass

def send_email(order):
    pass

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4. Use Comments Wisely

• Explain why, not what.

• Avoid obvious comments.

# Bad
x = x + 1  # increment x by 1

# Good
# Adjust index to match 1-based numbering
index += 1

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5. Error Handling

• Handle errors gracefully.

• Use exceptions rather than letting the program crash.

# Bad
file = open("data.txt")
data = file.read()
file.close()

# Good
try:
    with open("data.txt") as file:
        data = file.read()
except FileNotFoundError:
    print("File not found!")

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6. Avoid Magic Numbers and Strings

• Use constants for values that don’t change.

# Bad
if user_age < 18:
    print("You cannot vote")

# Good
MIN_VOTING_AGE = 18
if user_age < MIN_VOTING_AGE:
    print("You cannot vote")

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7. Modular Code

• Break code into modules/packages for scalability.

project/
│
├── utils.py        # helper functions
├── models.py       # data models
├── services.py     # business logic
└── main.py         # entry point

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8. Write Tests

• Always write unit tests for critical functions.

def add(a, b):
    return a + b

def test_add():
    assert add(2, 3) == 5
    assert add(-1, 1) == 0

• Python: pytest

• JS: Jest

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9. Use Version Control

• Commit code regularly with meaningful commit messages.

git add .
git commit -m "Fix: added validation for order input"
git push origin main

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10. Follow DRY Principle (“Don’t Repeat Yourself”)

• Avoid duplicating code. Reuse functions/classes.

# Bad
def calc_sum1(a, b):
    return a + b

def calc_sum2(x, y):
    return x + y

# Good
def calculate_sum(a, b):
    return a + b

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11. Optimize for Readability

• Code should be easier to read than to write.

• Prefer clarity over clever tricks.

# Bad
res=[i**2 for i in range(10) if i%2==0]

# Good
even_squares = []
for i in range(10):
    if i % 2 == 0:
        even_squares.append(i**2)

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12. Use Logging Instead of Print Statements

• Logs are easier to maintain in production.

import logging

logging.basicConfig(level=logging.INFO)
logging.info("Server started")

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Summary Table